The types of fertilizers is astounding, and various classifications aid in selecting the right one. Fertilizers are classified based on factors like chemical composition, nutrient content, fertilizer effect, acidity and alkalinity, form, and main function. These classifications include organic and inorganic fertilizers, single and compound fertilizers, fast-acting and slow-release fertilizers, as well as acid and alkaline fertilizers. By understanding these categories, we can choose suitable fertilizers to meet specific crop needs and preferences. This knowledge enables us to effectively manage soil fertility, boost crop yields, and ensure plants receive the necessary nutrients.
Classification by chemical composition
(1) Organic fertilizer
Refers to nitrogen-containing materials that are mainly derived from plants and animals and applied to the soil to improve plant nutrients, such as human excrement, poultry manure, compost, green manure, urban waste, soil inoculum, etc.
(2) Inorganic fertilizers
Inorganic fertilizers are produced through industrial methods, extracting nutrients as inorganic salts. Examples include urea, ammonium sulfate, ammonium bicarbonate, potassium sulfate, monoammonium phosphate, diammonium phosphate, superphosphate, potassium chloride, magnesium sulfate, calcium magnesium phosphate fertilizer, borax, zinc sulfate, and manganese sulfate. These, along with sulfur, calcium cyanide, urea, bone meal, and superphosphate, are categorized as inorganic fertilizers.
(3) Organic and inorganic fertilizers
products of organic and inorganic substances that indicate nutrients are made by mixing and compounding organic and inorganic fertilizers.
According to the amount of nutrients
(1) Single fertilizer
A general term for N, P, and K fertilizers that only have a declared amount of one of the three nutrients: N, P, and K. Such as urea, ammonium sulfate, ammonium bicarbonate, potassium sulfate, superphosphate, potassium chloride, magnesium sulfate, borax, zinc sulfate, sulfate, etc.
(2) Multi-nutrient fertilizers Compound fertilizers
Among the three nutrients N, P, and K, there are at least two nutrients in the indicated amount, and only chemically produced fertilizers. Such as monoammonium phosphate, diammonium phosphate, potassium nitrate, potassium dihydrogen phosphate, etc.
(3) Mixed fertilizer
a fertilizer prepared by mechanically mixing two or three N, P, K single fertilizers or one or two of compound fertilizers and N, P, K single fertilizers. It can be divided into powdery, granular mixed fertilizers and blended fertilizers. Such as various compound fertilizers.
Classified by Fertilizer Efficiency
(1) Quick-acting fertilizer
After this chemical fertilizer is applied to the soil, it dissolves in the soil solution and is absorbed by the crops, and it takes effect quickly. Most nitrogen fertilizer varieties, common calcium superphosphate in phosphate fertilizer, potassium sulfate and potassium chloride in potash fertilizer are all quick-acting chemical fertilizers. Quick-acting chemical fertilizers are generally used as topdressing fertilizers and can also be used as base fertilizers.
(2) Slow-acting fertilizer
These fertilizers, known as long-acting and slow-release fertilizers, slowly release nutrients over time, allowing continuous absorption by plants. They undergo a brief transformation before dissolving in the soil, resulting in long-lasting fertilizer effects.
Nutrient release in these fertilizers is solely determined by natural factors. Examples include calcium magnesium phosphate fertilizer, steel slag phosphate fertilizer, and various organic compounds like urea-formaldehyde.
Additives such as nitrification inhibitors and urease inhibitors, along with coated fertilizers like long-acting urea and sulfur-coated urea, enhance their slow-release properties. Adding ammonia to long-acting ammonium bicarbonate production can extend its effect from 30-45 days to 90-110 days, while increasing nitrogen utilization from 25% to 35%. Slow-release fertilizers are commonly used as base fertilizers.
(3) Controlled Releas0e fertilizer
Controlled-release fertilizers are slow-acting fertilizers with artificially designed nutrient release rates and timing. Different crops have specific nutrient requirements during various growth stages. Factors such as soil humidity, temperature, and pH influence nutrient release. Coating methods, using different materials, thicknesses, and film opening ratios, are the most effective means of controlling release rates.
Types of Fertilizers – pH
(1) Acidic chemical fertilizers
Acidic fertilizers can be divided into two types, one is chemically acidic, and its aqueous solution is acidic, such as ordinary calcium superphosphate, and the other is physiologically acidic, which is neutral in aqueous solution, but After being applied to the soil, part of it is absorbed by the crops, and the other part is left in the soil, which is acidic, such as ammonium chloride, ammonium sulfate, potassium sulfate, etc.
(2) Alkaline chemical fertilizers
Alkaline chemical fertilizers are divided into two types, one is chemically alkaline, and its aqueous solution is alkaline, such as liquid ammonia and ammonia water. The other is physiologically alkaline, its aqueous solution is neutral, but after it is applied to the soil, the part that is not absorbed by the crops remains alkaline in the soil, such as sodium nitrate, calcium nitrate, etc.
(3) Neutral chemical fertilizers
The aqueous solution of neutral chemical fertilizers is neither acidic nor alkaline, nor is it acidic or alkaline after being applied to the soil. Therefore it can be applied to any soil, such as urea.
Types of Fertilizers – Nutrients Contained
(1) Unit chemical fertilizer
Refers to those that only contain one of the three main nutrients: nitrogen, phosphorus, and potassium. They are also called elemental fertilizers. For example, ammonium sulfate contains only nitrogen, ordinary calcium superphosphate contains only phosphorus, and potassium sulfate contains only potassium.
(2) Multiple chemical fertilizers
Refers to fertilizers that contain two or more of the three main nutrients, such as ammonium phosphate containing nitrogen and phosphorus.
(3) Complete chemical fertilizer
Refers to the fact that chemical fertilizers contain various nutrients needed for crop growth and development.
Types of Fertilizers – Shape
(1) Solid fertilizer
The chemical fertilizers in the form of crystallization, granulation or powder are made in the factory, which is very suitable for the agricultural technology level of our country in terms of packaging, transportation and application.
(2) Liquid fertilizer
Chemical fertilizers made in liquid form in factories, such as liquid ammonia, ammonia water, solution fertilizers, and colloidal fertilizers, can be applied to rhizosphere soil or foliage. Its production cost is relatively low, but it requires corresponding storage and application. Machine tools, suitable for mechanized farmland. In particular, sustainable agricultural development is suitable for the requirements of my country’s water-saving agriculture.
(3) Gas fertilizer
During crop growth and maturity stages, particularly in facility agriculture like solar and plastic greenhouses, carbon dioxide replenishment is crucial for optimal photosynthesis. To address this in airtight greenhouse environments, automatic carbon dioxide generators are used alongside self-control and adjustment facilities. Supplementing carbon dioxide approximately five times per crop on average can increase yield by around 50%, with potential increases of up to 200%. Ammonium bicarbonate is commonly used in plastic greenhouses in my country for nitrogen fertilizer and carbon dioxide supplementation.
Types of Fertilizers – Mode of Action
(1) Direct chemistry
Fertilizers refer to chemical fertilizers that are directly used as sources of crop nutrients, such as nitrogen fertilizers, phosphorus fertilizers, potassium fertilizers, and micro-fertilizers.
(2) Indirect chemistry
Fertilizers refer to fertilizers whose main purpose is to improve soil physical, chemical and physiological properties, such as gypsum, lime, bacterial fertilizers, etc.
(3) Hormone Chemistry
Fertilizers refer to those chemical fertilizers that stimulate the growth of crops, such as humic acid fertilizers.